Devices for drying damp granules



g- 11, 1964 I w. GLATT ETAL 3,144,310

DEVICES FOR DRYING DAMP GRANULES Filed May 2, 1961 3 Sheets-Sheet 1INVENTORS Wee/vs? Lax-r f/Efi/mnw IEDM/MW ATTORNEYS Aug. 11, 1964 w.GLATT ETAL DEVICES FOR DRYING DAMP GRANULES S Sheets-Sheet 3 Filed May2, 1961 m \f g r Q3 W R N 1! 2% N w 1 )b w B 3am vii United StatesPatent 3,144,310 DEVICES FOR DRYING DAMP GRANULES Werner Glatt, Posttach23 (17b), Hatlingen, Baden, Germany, and Hermann Wiedmann, Rummingen,near Lorrach, Germany; said Wiedrnann assignor to said Glatt Filed May2, 1961, Ser. No. 107,260 Claims priority, application Germany May 3,1960 Claims. (Cl. 34186) The present invention relates to devices fordrying damp granules and more particularly to devices wherein thematerial to be treated is exposed to a current of dry, hot air forremoving its moisture content. Many methods are already known for dryingdamp granules, in which opentop and sieve-bottom containers areintroduced in an airtight manner into ducts and exposed to a dry-aircurrent produced by a fan and by heating elements, and remain thereuntil the product is dried. Then the air-current is interrupted and thecontainers taken out and replaced by new containers filled with dampgranules.

Our invention represents a further development and an essentialimprovement of these known arrangements. The arrangement according tothe invention is fit to dry 1000 kg. and more per hour, depending on themoisture content of the products. The new arrangement also contains fansand heating elements. It is one of the characteristic features that itcontains at least two air ducts, each provided with a heating device anda fan; it further contains a revolving stage and removably mountedthereon a number of containers having open tops and sieve bottoms. Thecontainers are brought into one of the air ducts by rotating the stage.The number of containers is preferably higher by one than that of thedrying ducts.

The apparatus may, for instance, comprise two drying ducts and arevolving stage with three product containers. The two ducts may beoperated in series or in parallel, that is, independently from oneanother. When the two ducts are connected in series it is possible toaccomplish the drying process of the granules of one of the containersin one duct and simultaneously to pre-dry the granules of the othercontainer in the other duct with the same drying air, whilst the thirdcontainer may be replaced, emptied or filled at the same time.

An embodiment of the invention will now be described with reference tothe accompanying drawings, in Which:

FIGURE 1 is a front view of a drying device according to the presentinvention, with parts broken away;

FIGURE 2 is a top plan view of the same arrangement;

FIGURE 3 is a sectional view according to the line III-III of FIGURE 2,substantially showing the inner structure of one-half of the device;

FIGURE 3A is a partial view of the device as shown in FIGURE 3,illustrating an alternate operative position on the sealing collars;

FIGURES-4A and 4B are partial views similar in direction to FIGURE 3 buttaken both according to the line IVIV of FIGURE 1, the two viewsillustrating alternate operative positions of certain elements;

FIGURE 5 is a partial, sectional view corresponding to the top centerportion of FIGURE 1, with certain elements shown in their alternateoperative positions; and

FIGURE 6 is a schematic illustration of the control 3,144,310 PatentedAug. 11, 1964 apparatus associated with the drying device, andcomprising portions of the FIGURES 2, 3, 4A and 5.

As can best be seen from FIGURES 1 through 3, the casing 1 comprises atop portion 2 and a bottom portion 3. Between the two portions there isa horizontal partition wall 29. The top portion 2 is bisected by avertical partition wall 24 which is interrupted underneath the wall 29as will be explained hereunder. To the left and right of wall 24, asviewed in FIGURES l and 2, the device has front wall portions 28, 28'provided with respective inspection windows 27, 27'. A short distancefrom the uppermost wall of the top portion 2, horizontal wall portions42, 42' are provided. It will be understood that the wall portions 28,42 and 28, 42 constitute respective left-hand and right-hand sections ofthe device, as viewed in FIGURES 1 and 2. The wall portions 42, 42define, on the one hand, upper compartments 43, 43' with said uppermostwall and, on the other hand, lower or filter compartments or chambers23, 23' with the Wall 29.

The compartments 43, 43 and 23, 23 do not extend the full depth of thedevice since the top portion 2 also has vertical partition wall portions22, 22' a short distance from the rearmost wall of the top portion. Asbest seen in FIGURES 1 and 2, the spaces between said rearmost Wall andthe wall portions 22, 22 are further partitioned by respective wallportions 26, 26'. To the left of these wall portions, the two sectionsof the device have respec tive compartments 30, 30 while to the right ofsaid wall portions, there are filter chambers 36, 36 which Widen towardtheir bottom portions. In the center of the bottom portion 3 a bearing 4is arranged for revolving stage 6 which is arranged at the locationwhere the wall 24 is interrupted, and is provided with a toothed rim 5.This toothed rim meshes with a pinion 7 driven by a motor 8. It will beunderstood that the drive of the revolving stage 6 can also be effectedby compressed air or by a pneumatic hydraulic mechanism.

The revolving stage 6 has three openings 13 each of which is capable ofreceiving one of three removable containers 9, 10 and 11; each containeris open on top and provided with a sieve bottom. In the position shownin the figures, the containers 10 and 11 are positioned above the airfunnels 12 and 12, respectively, while the third container 9 is above aflap 14. The flap 14 is pivotally mounted at a hinge 15 and can beopened and closed by pneumatic means 16. A rubber collar 17, 17' isfitted at the upper edges of the funnels 12, 12' which can be pressedagainst the revolving stage 6 by means of pneumatic means, e.g. as shownat 18', so that the containers 10 and 11 can be sealed hermeticallyagainst funnels 12, 12', respectively. Each collar has anaccordion-shaped portion, denoted 17a, 17a, which allows sealingengagement between funnels 12, 12 and the respective opening 13 of therevolving stage 6. FIG- URE 3 shows one of the collars, 17', inspaced-apart relation, while FIGURE 3A illustrates the interengagedposition, resulting as an effect of the respective pneumatic device 18'being operated. It will be noted that the elements 12, 17 are located inthe left-hand section of the device, as viewed in FIGURES l and 2, whilethe corresponding identical elements 12, 17 are seen in the right-handsection. For the sake of clarity, not all elements have been shown onboth sides; for example, the left-side pneumatic means 18 is notillustrated.

In the top portion 2 of the casing 1, within the compartments 43, 43'there are axial blowers 19, 19 which are driven by electromotors 21, 21for sucking air from the filter chambers 23, 23, respectively (seeFIGURE 3). The two filter chambers are equipped with filter bags 25, 25,respectively, which are closed at the top and open at the bottom. Thesuspension of the bags 25, 25' from the wall portions 42, 42 is made byconventional means. The bags are visible through the windows 27, 27'(see FIGURES 1 and 3). The bottom edge of each bag, protruding throughan appropriate aperture in the wall 29, is provided with a rubber collaras shown at 57 so that the containers 9-11 can be sealed hermeticallyagainst the ports of the air ducts. At 58, pneumatic means (similar to18) is shown for pressing the collar 57' against the top of thecontainer.

The funnels 12, 12' are connected with ducts, such as 33', throughintermediate ducts 32, 32', which are connected with heating chambers35, 35 provided with heating elements as shown at 34'; these are heatedelectrically or by steam or hot water. Above the heating chambers 35, 35the filter chambers 36, 36 are closed by bottoms such as 38' havingopenings adapted to receive air-inlet filters 37, 37'. The top portionsof the filter chambers are provided with suction pipes 39, 39' leadingto the open air. The compartments 43, 43 housing the fans or blowers 19,19 are connected to respective exhaust pipes 44, 44'.

The pipe 44' of the right-hand section of the drying arrangement and theadjoining suction pipe 39 of the left-hand section are provided withflaps 45b and 45a, respectively, adapted to be opened to the outside airor to interconnect the pipe sections 39 and 44' with each other. Theflap 45a is preferably linked (not shown) to the flap 45b so that bothpipes are simultaneously opened to the atmosphere, or connected with oneanother.

As can best be seen from FIGURES 4A and 4B, there are control flaps 40a,40a between the respective blower compartments 43, 43 and the exhaustpipes 44, 44'. Preferably linked to said flaps by conventionalmechanical or electrical means (not shown), are separate control flaps40b, 40b which are adapted to interconnect the compartments 30, 30 withthe filter chambers 23, 23. All the said flaps, including the flaps 45a,4512 discussed somewhat earlier, are pivotable around hinged axes asshown at 41 for flap 40a. It should be mentioned in this connection thatthe left-side counterparts of elements 33', 34, 38', 41', 57 and 58' arenot shown in the drawings for the sake of clarity. The co-operation ofthe various flaps and chambers will be described in detail somewhatlater. Control flaps 45a, 45b are best seen in FIGURE wherein theyprovide two separate paths for the drying air paths; the other operativeposition is shown in FIGURE 1, wherein said flaps force the air currentsequentially to pass through the ducts.

The left-side section of the top portion 2 is constructed analogously tothe right-side section. The compartment 43 in which the fan or blower 19is lodged communicates with pipe 44 over the control flap 40a. The aircompartment 30 and the filter chamber 23 can be interconnected by thecontrol fiap 40b coupled with the control flap 40a, interconnecting saidcompartments when the control flap 40a, closes the exhaust pipe 44. Inthe filter chamber 36 there are fitted the fresh air filters 37, and inthe heating chamber 35 underneath there are the heating elements 34.

As shown, the drying device consists of two independent drying ducts.The first one is used for performing the drying process and consists ofthe suction pipe 39', the fresh-air filter chamber 36, the heatingchamber 35', the ducts 33' and 32, the funnel 12', the filter bag 25',the filter chamber 23 for the outgoing air and the blower compartment43'. In this drying duct the product container 11 is placed. The sec-0nd duct, serving for pre-drying, consists of the suction pipe 39, thefresh-air filter chamber 36, the heating chamber 35, ducts (similar to33', 32) connecting the heating chamber 35 to the funnel 12, the funnel12, the filter bag 25, the outgoing filter chamber 23 and the blowercompartment 43. The product container 10 is adapted to be placed in thesecond drying duct. The two drying ducts of the device may be usedindependently from one another if the flaps 45a, 45b are in their positions shown in FIGURE 5. Each section operates then with its own inletor suction pipe 39, 39' and outlet or exhaust pipe 44, 44. The controlflaps 40a, 40a, 40b and 401; are in the positions indicated in FIGURE 48for this operation.

When the flaps 40a, 4012 and/or 40a, 401) are switched over to theirpositions shown in FIGURE 4A, the air cycle or cycles can be consideredshort-circuited with respect to the passages through chambers 35, 35,ducts 33, 33, 32, 32, the respective containers 10, 11, and filter bags25, 25'. This operational mode is used to vibrate the filter bags onelfect of the strong air current impinging on them within the filterchambers 23, 23' which are now in direct communication with the deliveryside of the blowers 19, 19' through the compartments 30, 30'. Thus theparticles of the dry material which may cling to the inner walls of thefilter bags, owing to the upward stream of hot air during the dryingprocess, will be shaken off and drop into the containers.

A control apparatus 20 is schematically indicated in FIGURES l, 2 andshown in more detail in FIGURE 6, the latter incorporating partial viewsof FIGURES 2, 3, 4A and 5. The apparatus contains all control elementswhich are necessary for controlling the individual operating parts ofthe drying device. These are the following: A switch 208 to turn on andotf the motor 8; a switch 218 for operating the pneumatic means 18and/or 58; a switch 240 to operate the control flaps 40a and 40a, 40band 40b, 45a and 45b; a switch 221 to turn on and 01f the electromotors21, 21; and, optionally, other switches, e.g. one designated 234, forswitching on and otf the heating elements 34, 34'.

It has been found advisable to provide the control apparatus with aprogramming attachment, e.g., as schematically shown at 260, adapted tocontrol the rotation of the stage 6 by as soon as the granules in thecontainer have been dried sufficiently in the right-hand section of thedevice. The control apparatus may also contain a control arm or disc(not shown) which successively operates the various switches.

For the sake of simplicity, FIGURE 6 only shows the most essential,aforementioned, switches, without illustrating the more intricatesimultaneous and consecutive switching operations. As a matter ofexample, the actuation of the control apparatus 20 may involve a sectionof switch 240 which controls the flaps 40a and 40a as well as thecoupled flaps 40b and 40b for short-circuiting both air cycles. Anothersection of switch 240 may be arranged for disenergizing, through theintermediary of valve 218, the pneumatic means, such as 18' and 58' sothat the stage 6 and the con tainers thereon are released. Still anotherswitch, cooperating with the switch shown at 208, and designated 208a,may turn on the motor 8 while the latter may be stopped by amicro-switch 208b, both being controlled by the revolving stage 6itself. A further section of the control apparatus may energize saidpneumatic means again to press the rubber collars such as 17' and 57toward the stage 6 and the product containers 10 and 11; another switchsection will bring back said control flaps in their initial position.Referring more particularly to the center portion of FIGURE 6,illustrating the control apparatus 20 and some of the elements containedtherein, it should be pointed out that all electrical mains leads arerepresented by heavy lines; all electrical control circuits by regularsolid lines; and all pneumatic lines (pipes) by dot-dash lines. For thesake of simplicity of illustration, the electrical lines have been shownas single lines, without so-called return branches. For the same reason,the dot-dash lines represent continuous pipe lines having the customarywalls.

The electric mains connection may include a conventional cut-off switchas shown at 202, adapted to disenergize the entire device. This isfollowed by switches 208 and 221 for energizing, according to therequired operational cycles, the motor 8 and the fan motors 21, 21'. Asmentioned before, switches for, and connectoins to, the other members,e.g. motor 21 or flaps 40a, 40b have not been shown in FIGURE 6. Theswitch 221 has a relay circuit which can manually be energized by meansof push-button 221a.

The electrical control or relay circuits are only schematically shown.Relays are identified by the letters R. The two relays forming part ofswitch system 208, for example, are respectively controlled bymicroswitches 208a, 2081) which, in turn, are acted upon by pegs or cams296 provided on the stage at about 120 apart.

The programming device 260 is schematically illustrated with a disc-typetimer graduated in periods of 10 minutes and 1, 2 and 3 hours. Amicro-switch 218a similarly operated by the cam 206 at stage 6, winds upa motor forming part of the programming device. Between the relaysacting upon the pneumatic switch 218 and those controlling the functionsof switch system 240, delay means 262 are intercalated which provide forthe required (approx. l2-second) timing between subsequent functions.

In the left-hand portion of FIGURE 6, a pneumatic means 16a hasadditionally been identified which cooperates with the flap operatingmeans 16 already mentioned. For these elements, another pneumatic switch216 is schematically shown, with a controlling relay, although thedot-dash line has not been connected to the compressed air input.

The method of operating can be understood from the foregoingdescription: For normal use the flaps 45a and 45b are in the position asshown in FIGURE 1, so that the two dry-air ducts are connected serially.The two pairs of rubber collars, e.g. 17 and 57' are pressed toward therevolving stage 6 and to the product containers l0 and 11, so that eachcontainer is made part of a dry-air duct. The axial blowers 19 and 19'are now both sucking the air through the closed and serially switchedducts, as described before, so as to dry the granules in the containers.As soon as the granules in the container 11 are sufiiciently dried themechanism will be released. This release can be executed by ahand-controlled switch or by a time switch, such as the programmingattachment 260, having an adjustable drying period, or by a switchcontrolled by the temperature in the pipe 44'. Any conventional controlmeans, e.g. a thermostat as shown at 46, may be provided for thispurpose. As soon as the revolving stage 6 is turned about 120, thecontainer containing the dried material can be replaced by anothercontainer which has in the meantime been filled. with material to bedried.

There is a possibility for pouring out the dry granules, and that is bythe help of the pneumatic means 16, by opening the flap 14, to dischargethe material in a known manner. To this end, switch 216 will controleither or both of the pneumatic means 16, 16a.

We claim:

1. A device for drying damp granular materials by means of a current ofhot, dry air, comprising at least two ducts for the passage of said air,at least three containers for temporarily storing said material duringits processing, a revolving stage having three openings at predeterminedlocations, means for removably supporting said containers thereat, twoof said locations substantially coinciding with the major directions ofsaid ducts while the third location serves for filling said materialinto one of said containers and for emptying the same therefrom, saidcontainers having open tops and perforated bottoms for the passage ofsaid air, said container tops and bottoms at said two locations, therespective stage openings and said major duct directions beingcollinearly arranged in two separate, substantially parallel paths forsuccessive flow of said air therethrough, a filter bag closed on top andinterposed in each of said ducts substantially above said containers,and inlet filter means in said ducts.

2. A device for drying damp granular materials by means of a current ofhot, dry air, comprising at least two ducts for the passage of said air,at least three containers for temporarily storing said material duringits processing, a revolving stage having three openings at predeterminedlocations, means for removably supporting said containers thereat, twoof said locations substantially coinciding with the major directions ofsaid ducts while the third location serves for filling said materialinto one of said containers and for emptying the same therefrom, saidcontainers having open tops and perforated bottoms for the passage ofsaid air, said container tops and hottoms at said two locations, therespective stage openings and said major duct directions beingcollinearly arranged in two separate, substantially parallel paths forsuccessive flow of said air therethrough, a filter bag closed on top andinterposed in each of said ducts substantially above said containers,inlet filter means in said ducts, and releasable and engageable sealingmeans in said ducts for selectively interconnecting the bottoms of saidfilter bags with the tops of said containers in a substantiallyair-tight manner, said air passing through the material in saidcontainers substantially upward into said filter bags.

3. A device for drying damp granular materials by means of a current ofhot, dry air, comprising at least two ducts for the passage of said air,at least three containers for temporarily storing said material duringits processing, a revolving stage having three openings at predeterminedlocations, means for removably supporting said containers thereat, twoof said locations substantially coinciding with the major directions ofsaid ducts while the third location serves for filling said materialinto one of said containers and for emptying the same therefrom, saidcontainers having open tops and perforated bottoms for the passage ofsaid air, said container tops and bottoms at said two locations, therespective stage openings and said major duct directions beingcollinearly arranged in two separate, substantially parallel paths forsuccessive flow of said air therethrough, a filter bag closed on top andinterposed in each of said ducts substantially above said containers,inlet filter means in said ducts, and means for closing the outlet of atleast one of said ducts and directing said air from the outside of thefilter bag of said one duct to its inside for vibrating said filter bagand thereby shaking off particles of said material adhering to saidfilter bag.

4. A device for drying damp granular materials by means of a current ofhot, dry air, comprising at least two ducts for the passage of said air,at least three containers for temporarily storing said material duringits processing, a revolving stage having three openings at predeterminedlocations, means for removably supporting said containers thereat, twoof said locations substantially coinciding with the major directions ofsaid ducts while the third location serves for filling said materialinto one of said containers and for emptying the same therefrom, saidcontainers having open tops and perforated bottoms for the passage ofsaid air, said container tops and bottoms at said two locations, therespective stage openings and said major duct directions beingcollinearly arranged in two separate, substantially parallel paths forsuccessive flow of said air therethrough, a filter bag closed on top andinterposed in each of said ducts substantially above said containers,inlet filter means in said ducts, releasable and engageable sealingmeans in said ducts for intercon- 7 meeting the bottoms of said filterbags with the tops of said containers in a substantially air-tightmanner, means for closing the outlet of at least one of said ducts anddirecting said air to the outside of the filter bag of said one duct,and control means for operating each of said revolving stage, saidsealing means, said closing means and for correlating their operation,in at least two consecutive drying cycles, so that said stage is rotatedbetween subsequent cycles by the angular distance between twoconsecutive containers, said sealing means is alternately engaged beforeand released after each cycle, said ducts are alternatelyshort-circuited for providing a single continuous path and separated forpresenting two separate paths for said air, and so that said closingmeans is operated in at least one cycle for vibrating the filter bag of15 said one duct.

5. A device for drying damp granular materials according to claim 4,further comprising temperature-responsive means for recycling theoperation of said control means in dependence of a low moisture contentvalue of the 5 escape air in at least one of the outlets of said ducts.

References Cited in the file of this patent UNITED STATES PATENTS620,139 Hysore Feb. 28, 1899 1,690,444 Dobblestein Nov. 6, 19282,256,017 Curran Sept. 16, 1941 FOREIGN PATENTS 1,025,916 Germany Mar.13, 1958 Patent No 3, 144,310 August 11, 1964 Werner Glatt et a1 It ishereby certified that ent requiringcorrection and that corrected below.

error appears in the above numbered patthe' said Letters Patentshouldread as In the grant, line 1, and in the headin specification, lines 3and 4, each occurrence,

g to the printed for Hatlingen, Baden, Germany", read Haltingen, Baden,Germany Signed and sealed this 5th day of January 1965.

(SEAL) Attest:

ERNEST'W.- SWIDER EDWARD J. BRENNER Mtesting Officer Commissioner ofPatents

1. A DEVICE FOR DRYING DAMP GRANULAR MATERIALS BY MEANS OF A CURRENT OFHOT, DRY AIR, COMPRISING AT LEAST TWO DUCTS FOR THE PASSAGE OF SAID AIR,AT LEAST THREE CONTAINERS FOR TEMPORARILY STORING SAID MATERIAL DURINGITS PROCESSING, A REVOLVING STAGE HAVING THREE OPENINGS AT PREDETERMINEDLOCATIONS, MEANS FOR REMOVABLY SUPPORTING SAID CONTAINERS THEREAT, TWOOF SAID LOCATIONS SUBSTANTIALLY COINCIDING WITH THE MAJOR DIRECTIONS OFSAID DUCTS WHILE THE THIRD LOCATION SERVES FOR FILLING SAID MATERIALINTO ONE OF SAID CONTAINERS AND FRO EMPTYING THE SAME THEREFROM, SAIDCONTAINERS HAVING OPEN TOPS AND PERFORATED BOTTOMS FOR THE PASSAGE OFSAID AIR, SAID CONTAINER TOPS AND BOTTOMS AT SAID TWO LOCATIONS, THERESPECTIVE STAGE OPENINGS AND SAID MAJOR DUCT DIRECTIONS BEINGCOLLINEARLY ARRANGED IN TWO SEPARATE, SUBSTANTIALLY PARALLEL PATHS FORSUCCESSIVE FLOW OF SAID AIR THERETHROUGH, A FILTER BAG CLOSED ON TOP ANDINTERPOSED IN EACH OF SAID DUCTS SUBSTANTIALLY ABOVE SAID CONTAINERS,AND INLET FILTER MEANS IN SAID DUCTS.